U.S. patent application number 12/337929 was filed with the patent office on 2010-06-24 for system and method for obtaining content from a content delivery network.
This patent application is currently assigned to AT&T CORP.. Invention is credited to Sunil Maloo.
Application Number | 20100161799 12/337929 |
Document ID | / |
Family ID | 42267704 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100161799 |
Kind Code |
A1 |
Maloo; Sunil |
June 24, 2010 |
System and Method for Obtaining Content from a Content Delivery
Network
Abstract
A method receives from a first server a first domain name system
(DNS) request including a first internet protocol (IP) address of
the first server, and a second IP address received by the first
server from a first system. The method also maps a correlation
between the first IP address and the second IP address, and
receives from the first server a second DNS request. In response to
receiving the second DNS request, the method responds to the first
server with a third IP address of a second server, wherein the
third IP address is chosen based upon the second IP address.
Inventors: |
Maloo; Sunil; (Edison,
NJ) |
Correspondence
Address: |
AT&T Legal Department - LNA;Attn: Patent Docketing
Room 2A- 207, One AT & T Way
Bedminster
NJ
07921
US
|
Assignee: |
AT&T CORP.
New York
NY
|
Family ID: |
42267704 |
Appl. No.: |
12/337929 |
Filed: |
December 18, 2008 |
Current U.S.
Class: |
709/226 |
Current CPC
Class: |
H04L 61/1511 20130101;
H04L 61/1552 20130101; H04L 29/12132 20130101; H04L 67/1036
20130101; H04L 29/12066 20130101; H04L 67/1002 20130101 |
Class at
Publication: |
709/226 |
International
Class: |
G06F 15/16 20060101
G06F015/16 |
Claims
1. A method comprising: receiving from a first server a first
domain name system (DNS) request including a first internet
protocol (IP) address of the first server, and a second IP address
received by the first server from a first system; mapping a
correlation between the first IP address and the second IP address;
receiving from the first server a second DNS request; and in
response to receiving the second DNS request, responding to the
first server with a third IP address of a second server, wherein
the third IP address is chosen based upon the second IP
address.
2. The method of claim 1 further comprising, in response to the
first DNS request, responding to the first server with a loopback
response.
3. The method of claim 1 wherein the second DNS request is received
by the first server from a second system.
4. The method of claim 3 wherein: the first DNS request is received
by a third server; and the mapping is done by the third server.
5. The method of claim 4 wherein the third server is a content
delivery network mapping server.
6. The method of claim 4 further comprising: in response to mapping
the correlation, receiving at a fourth server the mapping between
the first IP address and the second IP address; and wherein the
second DNS request is received by the fourth server.
7. The method of claim 6 wherein the second server, the third
server, and the fourth server comprise a content delivery
network.
8. The method of claim 1 wherein the first server is an Internet
Service Provider DNS server.
9. The method of claim 1 wherein the first system is a client of an
Internet Service Provider.
10. The method of claim 1 wherein the second server is a content
delivery network edge server.
11. A computer readable medium including instructions for carrying
out a method, the method comprising: receiving from a first server
a first domain name system (DNS) request including a first internet
protocol (IP) address of the first server, and a second IP address
received by the first server from a first system; mapping a
correlation between the first IP address and the second IP address;
receiving from the first server a second DNS request: and in
response to receiving the second DNS request, responding to the
first server with a third IP address of a second server, wherein
the third IP address is chosen based upon the second IP
address.
12. The computer readable medium of claim 11, the method further
comprising, in response to the first DNS request, responding to the
first server with a loopback response.
13. The computer readable medium of claim 11, wherein the second
DNS request is received by the first server from a second
system.
14. The computer readable medium of claim 11, wherein: the first
DNS request is received by a third server; and the mapping is done
by the third server.
15. The computer readable medium of claim 14, wherein the third
server is a content delivery network mapping server.
16. The computer readable medium of claim 15, the method further
comprising: in response to mapping the correlation, receiving at a
fourth server the mapping between the first IP address and the
second IP address; and wherein the second DNS request is received
by the fourth server.
17. The computer readable medium of claim 16, wherein the second
server, the third server, and the fourth server comprise a content
delivery network.
18. The computer readable medium of claim 11 wherein the first
server is an Internet Service Provider DNS server.
19. The computer readable medium of claim 11 wherein the first
system is a client of an Internet Service Provider.
20. The computer readable medium of claim 11 wherein the second
server is a content delivery network edge server.
Description
FIELD OF THE DISCLOSURE
[0001] The present disclosure generally relates to communications
networks, and more particularly relates to systems and methods for
directing content requests to servers.
BACKGROUND
[0002] Packet-switched networks, such as networks based on the
TCP/IP protocol suite, can distribute a rich array of digital
content to a variety of client applications. One popular
application is a personal computer browser for retrieving documents
over the Internet written in the Hypertext Markup Language (HTML).
Frequently, these documents include embedded content. Where once
the digital content consisted primarily of text and static images,
digital content has grown to include audio and video content as
well as dynamic content customized for an individual user.
[0003] It is often advantageous when distributing digital content
across a packet-switched network to divide the duty of answering
content requests among a plurality of geographically dispersed
servers. For example, popular Web sites on the Internet often
provide links to "mirror" sites that replicate original content at
a number of geographically dispersed locations. A more recent
alternative to mirroring is content distribution networks (CDNs)
that dynamically redirect content requests to an edge server
situated closer to the client issuing the request. CDNs either
co-locate edge servers within Internet Service Providers or deploy
them within their own networks.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] It will be appreciated that for simplicity and clarity of
illustration, elements illustrated in the Figures have not
necessarily been drawn to scale. For example, the dimensions of
some of the elements are exaggerated relative to other elements.
Embodiments incorporating teachings of the present disclosure are
shown and described with respect to the drawings presented herein,
in which:
[0005] FIG. 1 is a schematic diagram showing a communication
network, including an autonomous network and a content distribution
network (CDN);
[0006] FIG. 2 is a schematic illustration showing interactions
between elements of the communication network of FIG. 1 that
provide content from the CDN to a client system;
[0007] FIG. 3 is a schematic illustration showing downloading CDN
client software to the client system;
[0008] FIG. 4 is a schematic illustration showing interactions
between elements of the communication network after installing the
CDN client software on the client system;
[0009] FIG. 5 is a schematic illustration showing interactions
between elements of the communication network after the CDN
correlates an internet service provider's domain name system server
location to the client systems that are served by the internet
service provider;
[0010] FIG. 6 is a flow chart showing a method of determining the
location of a request on a CDN; and
[0011] FIG. 7 shows an illustrative embodiment of a general
computer system 700.
[0012] The use of the same reference symbols in different drawings
indicates similar or identical items.
DETAILED DESCRIPTION OF THE DRAWINGS
[0013] The numerous innovative teachings of the present application
will be described with particular reference to the presently
preferred exemplary embodiments. However, it should be understood
that this class of embodiments provides only a few examples of the
many advantageous uses of the innovative teachings herein. In
general, statements made in the specification of the present
application do not necessarily limit any of the various claimed
inventions. Moreover, some statements may apply to some inventive
features but not to others.
[0014] FIG. 1 shows a communication network 100. Communication
network 100 includes an autonomous network (AN) 110 and a content
distribution network (CDN) 140 that are connected together through
a network 102, such as the Internet. AN 110 includes routers 112,
114, and 116 that communicate with each other. AN 110 connects to
network 102 through routers 112, 114, and 116, permitting AN 110 to
connect to other ANs (not illustrated) in communication network
100, and otherwise gain access to resources and content on
communication network 100. AN 110 also includes client systems 122,
124, 126, and 128, and Internet service provider domain name system
(ISP DNS) server 130. Client system 122 is connected to router 112,
client systems 124 and 126 are connected to router 114, and client
system 128 and ISP DNS server 130 are connected to router 116.
Client systems 122, 124, 126, and 128, and ISP DNS server 130 gain
access to resources and content on communication network 100
through their respective routers 112, 114, and 116. As such, router
112 provides ingress and egress to communication network 100 for
client system 122, router 114 provides ingress and egress for
client systems 124 and 126, and router 116 provides ingress and
egress for client system 128 and for ISP DNS server 130. A
non-limiting example of a client system 122, 124, 126, or 128
includes a personal computer, a laptop computer, a set-top box, a
handheld computing device, another general purpose computing
system, or a combination thereof. In a particular embodiment (not
illustrated), one or more of routers 112, 114, and 116 are not
connected directly to network 102. For example, router 114 may not
be connected directly to network 102. Here client systems 124 and
126 obtain ingress and egress to communication network 100 through
router 114, and either router 112 or 116, depending upon routing
conditions in AN 110.
[0015] While not shown to scale, FIG. 1 represents client systems
122, 124, 126, and 128 as being in close proximity to each other,
and DNS ISP server 130 as being more remote from client systems
122, 124, 126, and 128. Client systems 122, 124, 126, and 128, and
DNS ISP server 130 each have a unique public routable Internet
Protocol (IP) address. For example, client system 122 can have an
IP address of 123.123.112.122, client system 124 can have an IP
address of 123.123.114.124, client system 126 can have an IP
address of 123.123.114.126, client system 128 can have an IP
address of 123.123.116.128, and DNS ISP server 130 can have an IP
address of 123.123.116.130. For example, client systems 122, 124,
126, and 128 can be located in New York City, and DNS ISP server
130 can be located in Chicago.
[0016] CDN 140 includes a content distribution network domain name
system (CDN DNS) server 142, and edge servers 144 and 146. CDN 140
is a distributed network, with edge servers 144 and 146 situated at
different locations in communication network 100. For example, edge
server 144 can be located in New Jersey, and edge server 146 can be
located in Chicago. CDN 140 connects to network 102 through peering
points at CDN DNS server 142, and edge servers 144 and 146. With
respect to communication network 100, the closest edge server may
be the edge server having a shortest network distance, a lowest
network cost, a lowest network latency, a highest link capacity,
another measure of proximity on a network, or any combination
thereof. As such, the distance between an edge server and a client
system may be different from the geographic distance. While CDN DNS
server 142 and edge servers 144 and 146 are shown as separate
elements, it is also possible that the functions of CDN DNS server
142, as described below, can be merged into one or more of edge
servers 144 and 146. It is also possible to locate CDN DNS server
142 and edge servers 144 and 146 within AN 110.
[0017] Client systems 122, 124, 126, and 128 can retrieve
information from communication network 100. For example, client
system 124 can retrieve a content provider's webpage, where the web
page content resides on a content server (not illustrated).
Additionally, client system 124 may download content files, such as
graphic, audio, and video content, and program files such as
software updates, from the content server. However, client systems
122, 124, 126, and 128 need to know the IP address of the content
server in order to retrieve the information.
[0018] When a user knows the IP address of the content server, then
the user can request the information directly from the content
server. However, it is more often the case that a user does not
know the IP address of the content server, but instead knows a
domain name associated with the desired content. For example, a
user of client system 124 may know that the desired information is
located on a server associated with the domain name "www.att.com."
In this case, the user can enter a Uniform Resource Locator (URL),
including the domain name, into client system 124. Client system
124 attempts to resolve the domain name into a known IP address of
the content server associated with the domain name. The resolution
is done by referring to an operating system host file that includes
a list of domain names and their associated IP addresses
(hereinafter referred to as domain name/IP address pairs). If the
OS host file includes a domain name/IP address pair for the domain
name in the URL, then client system 124 sends an information
request to the IP address of the content server associated with the
domain name, and the content server returns the requested
information.
[0019] When the OS host file does not include a domain name/IP
address pair for the domain name included in the URL, then client
system 124 sends a DNS request to ISP DNS server 130. The DNS
request is a request for ISP DNS server 130 to resolve the domain
name into the IP address of the content server associated with the
domain name. ISP DNS server 130 forwards the DNS request to an
authoritative DNS server (not illustrated) for the domain to which
the domain name belongs. The authoritative DNS server replies to
ISP DNS server 130 with the IP address of the content server
associated with the domain name, and ISP DNS server 130 in turn
replies to client system 124 with the IP address. Client system 124
then sends an information request to the IP address of the content
server, and the content server returns the requested information.
ISP DNS server 130 also stores the domain name/IP address pair in a
cache, so that, when ISP DNS server 130 receives a subsequent DNS
request, ISP DNS server 130 can attempt to resolve the domain name
by referring first to the cache. Then, if the cache includes the
domain name/IP address pair for the domain name in the DNS request,
then DNS ISP server 130 can reply directly to client system 124
without sending the DNS request to the authoritative DNS
server.
[0020] The time required for client system 124 to retrieve the
information from the content server normally relates to the size of
the file, the distance the information travels, and congestion
along the route. Additionally, the load on the content server is
related to the number of client systems 122, 124, 126, and 128 that
are actively retrieving information at the same time. Therefore,
resources such as processors, memory, and content server bandwidth
limit the number of client systems 122, 124, 126, and 128 that can
simultaneously retrieve information from the content server.
[0021] A content provider can use CDN 140 to reduce the load on the
content server. As such, edge servers 144 and 146 replicate the
information found on the content server at locations within
communication network 100 that are closer to client systems 122,
124, 126, and 128. When client system 122, 124, 126, or 128 request
information from the content provider, a request for DNS resolution
is sent to ISP DNS server 130. ISP DNS server 130 requests the IP
address corresponding to the domain name from the authoritative DNS
server. When the domain name is for a content provider that uses
CDN 140 to reduce the load on their content server, the
authoritative DNS server for that domain name is CDN DNS server
142. CDN DNS server 142 provides the IP address of a closer edge
server 144 or 146 based upon the source IP address of the DNS
request, that is, the IP address of ISP DNS server 130. ISP DNS
server 130 returns the IP address of the selected edge server 144
or 146 to the requesting client system 122, 124, 126, or 128. The
requesting client system 122, 124, 126, or 128 sends an information
request to the selected edge server 144 or 146, which returns the
requested information. CDN DNS server 142 determines which edge
server 144 or 146 to redirect the request to, based upon the
shortest network distance, the lowest network cost, the lowest
network latency, the highest link capacity, another measure of
proximity on a network, or any combination thereof. As such, the
distance between the selected edge server 144 or 146 and the
requesting client system 122, 124, 126, or 128 may be different
from the geographic distance. It is also possible for more than one
content provider to use the same CDN 140.
[0022] FIG. 2 illustrates interactions between elements of
communication network 100 to provide client system 122 with content
from CDN 140. When client system 122 desires to receive information
from a content provider that uses CDN 140, client system 122 sends
a DNS request 202 to ISP DNS server 130. ISP DNS server 130
attempts to resolve the IP address associated with the requested
domain name, translating the domain name into an IP address. If the
domain name/IP address pair is not in the cache of ISP DNS server
130, ISP DNS server 130 forwards a DNS request 204 to CDN DNS
server 142. DNS request 204 includes at least the domain name to be
resolved, and the source IP address of DNS request 204, that is,
the IP address of ISP DNS server 130. CDN DNS server 142 determines
which of edge servers 144 or 146 is closer to the source IP address
of DNS request 204. However, a different edge server 144 or 146 may
actually be closer to the source IP address of DNS request 202, but
the source IP address of DNS request 202 is masked by the actions
of ISP DNS 130.
[0023] Using the previous examples, based on the IP address of ISP
DNS server 130, located in Chicago, CDN DNS server 142 selects edge
server 146, also located in Chicago, as closer to the source of DNS
request 204, and sends a reply 206 to ISP DNS server 130 including
the IP address of edge server 146 as the location of the requested
information. ISP DNS server 130 the IP address of edge server 146
to client system 122 in a reply 208. Upon receipt of reply 208,
client system 122 sends an information request 210 for the
information to edge server 146. Edge server 146 sends a reply 212
with the requested information to client system 122. Although edge
server 144, located in New Jersey is actually closer to client
system 122, located in New York, CDN DNS server 142 selects edge
server 146 in Chicago to provide the requested information based
upon the source IP address of ISP DNS server 130 which is also in
Chicago. In other words, ISP DNS server 130 masks the origin of DNS
request 202, preventing CDN DNS server 142 from selecting the
closer of edge servers 144 and 146 to provide the response to
information request 210.
[0024] In an embodiment of the present disclosure, CDN DNS server
142, edge servers 144 or 146, or another server in CDN 140 can
determine if client systems 122, 124, 126, and 128 have requested
information from CDN 140 before, for example by examining cookies
on client systems 122, 124, 126, and 128. If client systems 122,
124, 126, and 128 have not previously requested information from
CDN 140, then in addition to redirecting client systems 122, 124,
126, and 128 to edge servers 144 and 146, CDN 140 can download CDN
client software (shown as element 300 in FIG. 3) to client systems
122, 124, 126, and 128. FIG. 3 illustrates downloading CDN client
software 300 to client system 122. CDN DNS server 142 sends a
request 302 to client system 122, prompting the user of client
system 122 to decide whether or not to download CDN client software
300. If the user of client system 122 decides to download CDN
client software 300, the user can so indicate, and client system
122 sends a reply 304 to CDN DNS server 142. Upon receiving reply
304, CDN DNS server 142 sends a download 306 to client system 122.
Download 306 includes CDN client software 300 that may be installed
on client system 122. In another embodiment, edge server 146, or
another server in CDN 140 (not illustrated) functions similarly to
CDN DNS server 142, by sending request 302, receiving reply 304,
and sending download 306. In another embodiment, sending request
302, receiving reply 304, and sending download 306 can be performed
by a combination of CDN DNS server 142, edge server 146, and
another server in CDN 140 (not illustrated). In yet another
embodiment (not illustrated), one or more of request 302, reply
304, and download 306 can pass through ISP DNS 130.
[0025] FIG. 4 illustrates interactions among elements of
communication network 100 after CDN client software 300 is
installed on client system 122. Here, client software 300 issues a
request 402 to CDN server 149 to determine the public routable IP
address of client system 122. CDN server 149 returns a reply 404
with the public routable IP address of client system 122, for
example "123.123.114.122." In another embodiment (not illustrated),
client software 300 issues request 402 to, and receives reply 404
from another server (not illustrated) in network 102, in AN 110, or
in CDN 140. Then client software 300 sends a DNS request 406 to ISP
DNS server 130. DNS request 406 includes a domain name with the
public routable IP address of client system 122 and the domain name
associated with DNS mapping server 148. For example, DNS request
406 can include the domain name
123-123-114-122.dns.mapping.att.com. ISP DNS server 130 attempts to
translate the domain name into an IP address. If the domain name/IP
address pair is not in the cache of ISP DNS server 130, ISP DNS
server 130 determines that DNS mapping server 148 is the
authoritative DNS server for the requested URL, and forwards a DNS
request 408 to DNS mapping server 148. DNS request 408 includes the
IP address of ISP DNS server 130 as the source IP address of
request 408, and the public routable IP address of client system
122. DNS mapping server 148 sends a reply 410 to DNS ISP server,
which in turn forwards a reply 412 to client system 122. Replies
410 and 412 can be a valid response, such as a "non-existent
domain" (NXDOMAIN) reply, a loopack address (127.0.0.1), or another
valid response.
[0026] With both the public routable IP address of client system
122 and the IP address of ISP DNS server 130 as the source IP
address, DNS mapping server 148 correlates ISP DNS server 130, in
Chicago in the above example, with client system 122, in New York
City. Using this information, CDN 140 can predict that other
requests routed through ISP DNS server 130 might also be
originating from locations in the same area, New York City, even
though ISP DNS server 130 is located in Chicago. For example, FIG.
5 illustrates interactions between elements of communication
network 100 after CDN 140 correlates ISP DNS server 130 with the
location of client systems 122, 124, 126, and 128 that are served
by ISP DNS server 130.
[0027] When client system 124 desires to receive information from
CDN 140, client system 124 sends a request 502 to ISP DNS server
130. ISP DNS server 130 attempts to translate the domain name into
an IP address. If the domain name/IP address pair is not in the
cache of ISP DNS server 130, ISP DNS server 130 determines that CDN
DNS server 142 is the authoritative DNS server for the requested
domain, and forwards a request 504 to CDN DNS server 142. Request
504 includes at least the IP address of CDN DNS 142, the domain
name that needs to be resolved, and the IP address of ISP DNS
server 130 as the source IP address of request 504. CDN DNS server
142 recognizes ISP DNS server 130 as the source of request 504, and
although ISP DNS server 130 is located in Chicago, CDN DNS server
142 predicts that the source IP address of the real requester,
client system 124, is located close to client system 122, in New
York City. Based on this prediction, CDN DNS server 142 determines
that edge server 144 located in New Jersey is closer and may
provide content more efficiently to the real requester, client
system 124. Thus CDN DNS server 142 then sends a reply 506 to ISP
DNS server 130 that includes the IP address of edge server 144 as
the location of the requested information. ISP DNS server 130 sends
a reply 508 to client system 124 that includes the IP address of
edge server 144, as received from CDN DNS server 142. Upon receipt
of the reply 508, client system 124 sends a request 510 for the
information to edge server 144. Edge server 144 provides the
requested information 512 to client system 124. Note that, because
CDN 140 has correlated requests from ISP DNS server 130, in
Chicago, to client systems 122, 124, 126, and 128, in New York
City, CDN 140 more accurately predicts the actual location of
requests handled by ISP DNS server 130.
[0028] FIG. 6 illustrates a method of determining the location of a
request on a CDN. A request is received by a CDN mapping server in
block 602. For example, a client system can initiate a DNS request
that includes the host name of a CDN mapping server, which the ISP
DNS server forwards to the CDN mapping server. A decision is made
as to whether or not the request includes a client IP address in
decision node 604. If not, then the "NO" branch of decision node
604 is taken, and processing ends at block 606. If the request
includes a client IP address, then the "YES" branch of decision
node 604 is taken and the client IP address is mapped to the source
IP address of the request in block 608. For example, the mapping
server can include a mapping table or database that correlates
received client IP addresses with the associated ISP DNS servers
that send the requests.
[0029] In a particular embodiment, the CDN mapping server and the
CDN DNS server are separate servers. In this case, the CDN mapping
server sends the mapping information to the CDN DNS server in block
610. The CDN DNS server receives a DNS request in block 612. A
decision is made as to whether or not the source address of the DNS
request is included in the mapping information in decision node
614. If not, then the "NO" branch of decision node 614 is taken,
and the CDN DNS server determines the IP address of a CDN edge
server that is closer to the ISP DNS server, and responds to the
DNS request in block 616, and processing ends in block 606. If the
source address of the DNS request is included in the mapping
information, then the "YES" branch of decision node 614 is taken,
and the associated client IP address is determined from the mapping
information in block 618. The CDN DNS server determines the IP
address of a CDN edge server that is closer to the client IP
address, and responds to the DNS request in block 620, and
processing ends in block 606.
[0030] In another embodiment, a client system can be pre-populated
with CDN client software from the CDN. For example, a computer
manufacturer may desire to promote the services of a particular
content provider, and so may include pre-populated software on
their computer products that advertise for the particular content
provider. Here, it may be an additional benefit to the content
provider and to the computer manufacturer to speed up access to the
content provider's content by including CDN client software with
the pre-populated software.
[0031] FIG. 7 shows an illustrative embodiment of a general
computer system 700. The computer system 700 can include a set of
instructions that can be executed to cause the computer system to
perform any one or more of the methods or computer based functions
disclosed herein. The computer system 700 may operate as a
standalone device or may be connected, such as by using a network,
to other computer systems or peripheral devices.
[0032] In a networked deployment, the computer system may operate
in the capacity of a server or as a client user computer in a
server-client user network environment, or as a peer computer
system in a peer-to-peer (or distributed) network environment. The
computer system 700 can also be implemented as or incorporated into
various devices, such as a personal computer (PC), a tablet PC, an
STB, a personal digital assistant (PDA), a mobile device, a palmtop
computer, a laptop computer, a desktop computer, a communications
device, a wireless telephone, a land-line telephone, a control
system, a camera, a scanner, a facsimile machine, a printer, a
pager, a personal trusted device, a web appliance, a network
router, switch or bridge, or any other machine capable of executing
a set of instructions (sequential or otherwise) that specify
actions to be taken by that machine. In a particular embodiment,
the computer system 700 can be implemented using electronic devices
that provide voice, video or data communication. Further, while a
single computer system 700 is illustrated, the term "system" shall
also be taken to include any collection of systems or sub-systems
that individually or jointly execute a set, or multiple sets, of
instructions to perform one or more computer functions.
[0033] The computer system 700 may include a processor 702, such as
a central processing unit (CPU), a graphics processing unit (GPU),
or both. Moreover, the computer system 700 can include a main
memory 704 and a static memory 706 that can communicate with each
other via a bus 708. As shown, the computer system 700 may further
include a video display unit 710 such as a liquid crystal display
(LCD), an organic light emitting diode (OLED), a flat panel
display, a solid-state display, or a cathode ray tube (CRT).
Additionally, the computer system 700 may include an input device
712 such as a keyboard, and a cursor control device 714 such as a
mouse. Alternatively, input device 712 and cursor control device
714 can be combined in a touchpad or touch sensitive screen. The
computer system 700 can also include a disk drive unit 716, a
signal generation device 718 such as a speaker or remote control,
and a network interface device 720 to communicate with a network
726. In a particular embodiment, the disk drive unit 716 may
include a computer-readable medium 722 in which one or more sets of
instructions 724, such as software, can be embedded. Further, the
instructions 724 may embody one or more of the methods or logic as
described herein. In a particular embodiment, the instructions 724
may reside completely, or at least partially, within the main
memory 704, the static memory 706, and/or within the processor 702
during execution by the computer system 700. The main memory 704
and the processor 702 also may include computer-readable media.
[0034] The illustrations of the embodiments described herein are
intended to provide a general understanding of the structure of the
various embodiments. The illustrations are not intended to serve as
a complete description of all of the elements and features of
apparatus and systems that utilize the structures or methods
described herein. Many other embodiments may be apparent to those
of skill in the art upon reviewing the disclosure. Other
embodiments may be utilized and derived from the disclosure, such
that structural and logical substitutions and changes may be made
without departing from the scope of the disclosure. Additionally,
the illustrations are merely representational and may not be drawn
to scale. Certain proportions within the illustrations may be
exaggerated, while other proportions may be minimized. Accordingly,
the disclosure and the FIGs. are to be regarded as illustrative
rather than restrictive.
[0035] The Abstract of the Disclosure is provided to comply with 37
C.F.R. .sctn. 1.72(b) and is submitted with the understanding that
it will not be used to interpret or limit the scope or meaning of
the claims. In addition, in the foregoing Detailed Description of
the Drawings, various features may be grouped together or described
in a single embodiment for the purpose of streamlining the
disclosure. This disclosure is not to be interpreted as reflecting
an intention that the claimed embodiments require more features
than are expressly recited in each claim. Rather, as the following
claims reflect, inventive subject matter may be directed to less
than all of the features of any of the disclosed embodiments. Thus,
the following claims are incorporated into the Detailed Description
of the Drawings, with each claim standing on its own as defining
separately claimed subject matter.
[0036] The above disclosed subject matter is to be considered
illustrative, and not restrictive, and the appended claims are
intended to cover all such modifications, enhancements, and other
embodiments which fall within the true spirit and scope of the
present disclosed subject matter. Thus, to the maximum extent
allowed by law, the scope of the present disclosed subject matter
is to be determined by the broadest permissible interpretation of
the following claims and their equivalents, and shall not be
restricted or limited by the foregoing detailed description.
* * * * *